This is satellite data, not the frequently-and-mysteriously adjusted surface data. But I'm pretty unhappy after digging into the details and finding out that this data is adjusted, too:
One might ask, Why do the satellite data have to be adjusted at all? If we had satellite instruments that (1) had rock-stable calibration, (2) lasted for many decades without any channel failures, and (3) were carried on satellites whose orbits did not change over time, then the satellite data could be processed without adjustment. But none of these things are true. Since 1979 we have had 15 satellites that lasted various lengths of time, having slightly different calibration (requiring intercalibration between satellites), some of which drifted in their calibration, slightly different channel frequencies (and thus weighting functions), and generally on satellite platforms whose orbits drift and thus observe at somewhat different local times of day in different years. All data adjustments required to correct for these changes involve decisions regarding methodology, and different methodologies will lead to somewhat different results. This is the unavoidable situation when dealing with less than perfect data.This makes me grumpy.
I don't like adjustments to data, and I don't like accepting them because I like the scientists better or because the results agree with my world view. And the changes seem (to me, anyway) pretty significant: